Pugs are prone to testicular cancer when they aren't neutered. Treatment is castration and chemotherapy, if needed. If not an agressive cancer, most dogs get through it just fine.
If the cancer has not spread, the easiest solution is to neuter your dog. Spaying or neutering your pet is the most effective way of avoiding reproduction-related cancers.
Testicular cancer in general, affects male dogs. Difficulty in urinating or blood in the urine Weight loss,Loss of appetite,Blood discharge from vomiting,Abdominal swelling that continue to grow
What you need to know about testicular is that you should def. be taking to a specialist and getting it treated and that it can spread butcan be cured.